Code

chart = {
  const links = data.links.map(d => Object.create(d));
  const nodes = data.nodes.map(d => Object.create(d));

  const simulation = d3.forceSimulation(nodes)
      .force("link", d3.forceLink(links).id(d => d.id).distance(100))
      .force("charge", d3.forceManyBody().strength(-200))
      .force('collision', d3.forceCollide().radius(10))
      .force("center", d3.forceCenter(width / 2, height / 2));

  const svg = d3.select(DOM.svg(width, height));

  const link = svg.append("g")
      .attr("stroke-opacity", 0.2)
    .selectAll("path")
    .data(links)
    .join("path")
      .attr("stroke-width", 2)
      .attr("stroke", color)
      .attr("fill", "transparent");

  const node = svg.append("g")
      .attr("stroke", "#fff")
      .attr("stroke-width", 0)
    .selectAll("circle")
    .data(nodes)
    .join("circle")
      .attr("r", 6)
      .attr("fill", "#555")
      .call(drag(simulation))
   .on('click', function(d, i) {
      if(d.loc === "_blank") {
          var win = window.open(d.url, '_blank');
          win.focus()
      } else {
        window.location.href = d.url; 
      }
    })
  .on('mouseover', function(d) {
        d3.select(this).style("cursor", "pointer"); 
      })
  
  const textElements = svg.append('g')
    .selectAll('text')
    .data(nodes)
    .enter().append('text')
      .text(node => node.id)
      .attr('font-size', 10)
      .attr("font-family", "Helvetica")
      .attr("fill", "#555")
      .attr('dx', 10)
      .attr('dy', 4)

  simulation.on("tick", () => {
    link
      .attr("d", function(d) {
      var dx = d.target.x - d.source.x,
          dy = d.target.y - d.source.y,
          dr = Math.sqrt(dx * dx + dy * dy);
      return "M" + d.source.x + "," + d.source.y + "A" + dr + "," + dr + " 0 0,1 " + d.target.x + "," + d.target.y;
  });
    
    textElements
        .attr("x", node => node.x)
        .attr("y", node => node.y)
    
    node
        .attr("cx", d => d.x)
        .attr("cy", d => d.y);
  });

  invalidation.then(() => simulation.stop());
  
  return svg.node();
}
data = FileAttachment("bigrams_cars.json").json()

height = 600
color = {
  const scale = d3.scaleOrdinal(d3.schemeSet1);
  return d => scale(d.group);
}
drag = simulation => {
  
  function dragstarted(d) {
    if (!d3.event.active) simulation.alphaTarget(0.3).restart();
    d.fx = d.x;
    d.fy = d.y;
  }
  
  function dragged(d) {
    d.fx = d3.event.x;
    d.fy = d3.event.y;
  }
  
  function dragended(d) {
    if (!d3.event.active) simulation.alphaTarget(0);
    d.fx = null;
    d.fy = null;
  }
  
  return d3.drag()
      .on("start", dragstarted)
      .on("drag", dragged)
      .on("end", dragended);
}